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A053067
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a(n) = concatenation of next n numbers (omit leading 0's).
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18
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1, 23, 456, 78910, 1112131415, 161718192021, 22232425262728, 2930313233343536, 373839404142434445, 46474849505152535455, 5657585960616263646566, 676869707172737475767778
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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REFERENCES
| Felice Russo, A set of new Smarandache functions, sequences and conjectures in number theory, American Research Press 2000
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LINKS
| M. L. Perez et al., eds., Smarandache Notions Journal
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FORMULA
| a(n)=n^2/2+n/2+Sum{k=1..n-1}{(n^2/2+n/2-k)*10^Sum{j=0..k-1}{floor[1+log10(n^2/2+n/2-j)]}} [From Paolo P. Lava (paoloplava(AT)gmail.com), Dec 16 2008]
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MAPLE
| P:=proc(i) local a, k, j, n; for n from 1 by 1 to i do a:=n^2/2+n/2+sum('(n^2/2+n/2-k)*10^sum('floor(1+evalf(log10(n^2/2+n/2-j)))', 'j'=0..k-1)', 'k'=1..n-1); print(a); od; end: P(100); [From Paolo P. Lava (paoloplava(AT)gmail.com), Dec 16 2008]
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CROSSREFS
| Sequence in context: A001369 A007923 A080479 * A036906 A134733 A095256
Adjacent sequences: A053064 A053065 A053066 * A053068 A053069 A053070
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KEYWORD
| easy,base,nonn
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AUTHOR
| Felice Russo (frusso(AT)micron.com), Feb 25 2000
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EXTENSIONS
| More terms from James A. Sellers (sellersj(AT)math.psu.edu), Feb 28 2000
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